From fab326eca12963accac5bb884ac87fad7ee51c01 Mon Sep 17 00:00:00 2001
From: "CJACK." <tetr20071102@gmail.com>
Date: Thu, 5 Mar 2026 18:20:42 +0800
Subject: [PATCH] =?UTF-8?q?fix:=20=E4=BF=AE=E5=A4=8D=E5=B7=A5=E5=85=B7?=
 =?UTF-8?q?=E5=8E=86=E5=8F=B2=E6=B3=A8=E5=85=A5=20null=20=E5=AF=BC?=
 =?UTF-8?q?=E8=87=B4=E8=B0=83=E7=94=A8=E6=A0=BC=E5=BC=8F=E6=B7=B7=E4=B9=B1?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 internal/adapter/openai/message_normalize.go  |  3 ++
 .../adapter/openai/message_normalize_test.go  | 30 +++++++++++++++++++
 2 files changed, 33 insertions(+)

diff --git a/internal/adapter/openai/message_normalize.go b/internal/adapter/openai/message_normalize.go
index 299f908..bbc5800 100644
--- a/internal/adapter/openai/message_normalize.go
+++ b/internal/adapter/openai/message_normalize.go
@@ -132,6 +132,9 @@ func formatToolResultForPrompt(msg map[string]any) string {
 }
 
 func normalizeOpenAIContentForPrompt(v any) string {
+	if v == nil {
+		return ""
+	}
 	switch x := v.(type) {
 	case string:
 		return x
diff --git a/internal/adapter/openai/message_normalize_test.go b/internal/adapter/openai/message_normalize_test.go
index ba17a52..a4e1843 100644
--- a/internal/adapter/openai/message_normalize_test.go
+++ b/internal/adapter/openai/message_normalize_test.go
@@ -194,6 +194,36 @@ func TestNormalizeOpenAIMessagesForPrompt_PreservesConcatenatedToolArguments(t *
 	}
 }
 
+func TestNormalizeOpenAIMessagesForPrompt_AssistantNilContentDoesNotInjectNullLiteral(t *testing.T) {
+	raw := []any{
+		map[string]any{
+			"role":    "assistant",
+			"content": nil,
+			"tool_calls": []any{
+				map[string]any{
+					"id": "call_screenshot",
+					"function": map[string]any{
+						"name":      "send_file_to_user",
+						"arguments": `{"file_path":"/tmp/a.png"}`,
+					},
+				},
+			},
+		},
+	}
+
+	normalized := normalizeOpenAIMessagesForPrompt(raw, "")
+	if len(normalized) != 1 {
+		t.Fatalf("expected one normalized message, got %d", len(normalized))
+	}
+	content, _ := normalized[0]["content"].(string)
+	if strings.Contains(content, "<｜Assistant｜>null") || strings.HasPrefix(strings.TrimSpace(content), "null") {
+		t.Fatalf("unexpected null literal injected into assistant tool history: %q", content)
+	}
+	if !strings.Contains(content, "function.name: send_file_to_user") {
+		t.Fatalf("expected tool history block preserved, got %q", content)
+	}
+}
+
 func TestNormalizeOpenAIMessagesForPrompt_DeveloperRoleMapsToSystem(t *testing.T) {
 	raw := []any{
 		map[string]any{"role": "developer", "content": "必须先走工具调用"},